Direct Plasma Disinfection of Green Mold Spore on Citrus by Atmospheric Pressure Dielectric Barrier Discharge for Agricultural Applications

Abstract

Disinfecting effect on plasma generated by an atmospheric pressure dielectric barrier discharge, APDBD, was investigated to inactivate green mold spore, Penicillium digitatum, surviving on citrus fruit in an open environment. Aluminium electrode covered by dielectric silicon sheet from 0.05 mm to 5.0 mm in thickness was prepared as APDBD electrode, and plasma was generated on the surface of Citrus unshiu. As an optical emission of plasma, N₂ second positive band indicates high intensity, and also O radical at 777 nm were observed as a dominant for the inactivation of P. digitatum spore. The green mold spore was inactivated sufficiently by APDBD plasma exposure in a few seconds without any damage on the surface of citrus, though thermal damage of citrus surface occurs when surface temperature increased over 65 degrees C after tens of seconds in irradiation period.